1. Field of the Invention
The present invention relates to novel 6-oxabicyclo[3.2.2]nonan-4-ones, their corresponding alcohols and ethers, to use of the ethers for controlling plant growth and as herbicides and to herbicidal and plant growth regulating compositions containing these novel ethers.
2. Summary of the Invention
The present invention is directed to novel compounds of the formula I ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 each independently is a hydrogen atom or an alkyl group containing from 1 to 10 carbon atoms and R is an optionally-substituted unsaturated group containing up to 4 carbon atoms, a cycloalkyl group containing from 3 to 10 carbon atoms, a secondary alkyl group containing from 3 to 10 carbon atoms, or an aromatic or heterocyclic group containing up to 14 carbon atoms. The compounds are useful as herbicides and to control the growth of plants.
Non-limiting examples of species of the compounds of formula I of the invention include:
4-(2-fluorobenzyloxy)-5,7,7-triethyl-6-oxabicyclo[3.2.2]nonane, PA0 4-(2-pyridinylmethoxy)-5,7,7-trimethyl-6-oxabicyclo[3.2.2]nonane, PA0 4-(2-methylbenzyloxy)-7,7-dimethyl-5-ethyl-6-oxabicyclo[3.2.2]nonane, PA0 4-(2-propynyloxy)-5,7,7-trimethyl-6-oxabicyclo[3.2.2]nonane, PA0 4-(2-pyrimidinylmethoxy)-5,7,7-trimethyl-6-oxabicyclo[3.2.2]nonane, PA0 4-(tetrahydro-2-pyranylmethoxy)-5,7,7-trimethyl-6-oxabicyclo[3.2.2]nonane.
In the derivatives of formula I, preferably each R.sup.1, R.sup.2 and R.sup.3 is independently a hydrogen atom, a methyl group or an ethyl group. In one embodiment of the invention, each R.sup.1, R.sup.2 and R.sup.3 is the same and is preferably a methyl group.
In the derivatives of formula I, preferably R is an ethynyl group, a 2-pyridinyl group or a phenyl group optionally substituted by 1 or 2 chlorine or fluorine atoms or methyl groups. In one embodiment of the invention, R is a 2-chlorophenyl, a 2-fluorophenyl, a 2-methylphenyl group or a phenyl group.
Compounds that possess substantially the same plant growth regulator or herbicidal utility as those of formula I described herein and which can be prepared in like manner are equivalents thereof and include compounds wherein, for example, R is an unsaturated, aromatic or heterocyclic moiety, or cyclopropyl or 1-methylcyclopropyl, including but not limited to cyano, naphthyl, imidazolyl, triazolyl, thiadiazolyl, 2-quinolinyl, 1-isoquinolinyl, pyrrolyl, cyclohexenyl, N-methylimidazol-2-yl, N-methylpyrazol-2-yl, isoxazolyl, oxazolyl, isothiazolyl, thiazolyl, thienyl, 5-methyl-2-furanyl, triazinyl, pyrimidinyl, and the like.
The derivatives of formula I of the invention exhibit geometrical and optical isomerism and may be prepared in geometrical and/or optical forms, and as racemates. The various individual optical and geometrical forms and various combinations of the derivatives of the invention usually have some difference in herbicidal or plant growth control properties. The present invention contemplates all these active forms. The derivatives of formula I that have the RCH.sub.2 O group syn (with respect to the oxygen bridge) usually have the highest activity. Moreover, the derivatives of the formula I of the inventions also are useful as solvents or dispersing agents, e.g. for paints, pigments, polymers and synthetic fibers, and as plastisizers, e.g. for vinyl resins. These latter uses are irrespective of stereoisomerism.
The derivatives of formula I of the invention are prepared by an etherification reaction which introduces the group CH.sub.2 R. The etherification is conducted by treating the corresponding 6-oxabicyclo[3.2.2]nonan-4-ol derivative with a compound of the formula RCH.sub.2 X in which R is defined as in formula I above and X is a halogen atom, such as bromine, chlorine or iodine, or is a mesyloxy, tosyloxy group or the like, in the presence of a base and, preferably, an inert diluent. The base is suitably an alkali metal hydride, hydroxide or carbonate, including, for example, sodium hydride, sodium hydroxide, potassium carbonate and the like. Inert diluents (solvents) are suitably organic solvents, such as ethers, aromatic hydrocarbons and the like, including, for example, diethyl ether, tetrahydrofuran, dimethyl sulfoxide, toluene, methylene chloride and the like. The reaction is usually carried out under normal pressures and ambient temperatures. Suitable temperatures of the reaction include those from about 0.degree. C. to about 120.degree. C., preferably from about 20.degree. C. to about 100.degree. C. The reaction can be conducted in a two-phase system preferably in the presence of a phase-transfer catalyst. For example, such a system is an aqueous sodium or potassium hydroxide solution with toluene or methylene chloride with a catalyst, such as an ammonium compound, including tetra-n-butylammonium chloride, bromide or hydrogen sulfate, triethylbenzylammonium chloride and the like.
The derivatives of formula I are recovered and isolated by conventional techniques.
The corresponding 6-oxabicyclo[3.2.2]nonan-4-ols and 6-oxabicyclo[3.2.2]nonan-4-ones are also novel derivatives and have the formula II ##STR3## wherein each R.sup.1, R.sup.2 and R.sup.3 is independently a hydrogen atom or an alkyl group containing from 1 to 10 carbon atoms; and X is --OH or .dbd.O. In the novel derivatives of formula II, preferably each R.sup.1, R.sup.2 and R.sup.3 is independently a hydrogen atom, a methyl or ethyl group. In one embodiment of the invention, R.sup.1, R.sup.2 and R.sup.3 are the same and preferably each is a methyl group.
The derivatives of formula II are prepared by multistep conventional procedures known in the art from a 2-oxocyclopentanecarboxylic acid ester. This known ester is subjected to Michael addition in toluene with an alkyl vinyl ketone, e.g., at room temperature in the presence of triethylamine similar to the method of Dauben, W. G., et al, JACS, (1960), 82, page 4245. The resulting addition product is cyclized, e.g., at room temperature with sulfuric acid similar to the method of Evans, et al.. J. Chem. Soc. Chem. Comm., (1982) page 1342, to give the novel lactones of the formula III ##STR4## in which Z is the residue of an esterifying group, and Y is an alkyl group containing from 1 to 4 carbon atoms. Any esterifying group, organic or inorganic, which will not interfere with the reaction can be used for Z. For convenience, Y and Z each independently is an alkyl group containing from 1 to 10 carbon atoms. For example, Y and Z each independently is a methyl or ethyl group. In one embodiment of the invention, Y is a methyl group and Z is an ethyl group.
The lactone of formula III is treated with a strong acid at elevated temperature to give a mixture of unsaturated cycloheptenyl diesters, which are mono-decarboxylated, e.g., by treatment with aqueous sodium chloride and dimethyl sulfoxide at elevated temperatures. The resultant corresponding mixture of unsaturated mono-esters is treated with an appropriate Grignard reagent, e.g., alkylMgBr, in which the alkyl portion corresponds to one of the geminal alkyl substituent desired at the 7 position in formula II to give a mixture containing, e.g., the alpha,alpha,5-trialkyl-5-cycloheptene-1-methanol derivative.
This alcohol mixture is epoxidized and cyclized, e.g., by treatment with a peroxy acid followed by an acid, such as p-toluene-sulfonic acid, to give on separation the desired 6-oxabicyclo[3.2.2]nonan-4-one of formula II, which is converted into the corresponding exo-alcohol, a 6-oxabicyclo[3.2.2]nonan-4-ol, e.g., by treatment with a suitable agent, such as L-selectride. This ketone also is converted into predominantly the endo-alcohol by reduction, e.g., with sodium borohydride in ethanol.
One alternative procedure, is to start from cyclopentanone itself. After its Michael addition with an alkyl vinyl ketone as described above, the resulting product is cyclized with sulfuric acid as described above to give a lactone which is heated with acid and ethanol to give the ring-cleaves mixture of desired ethyl 3- (and 4-)cycloheptenecarboxylates for subsequent treatment with Grignard reagent, epoxidation and cyclization as described above to yield the desired alcohol of formula II.
The invention also includes a method of influencing agent growth and combatting unwanted plants which comprises applying to the locus an effective amount of a compound of Formula I. For example, the compounds of formula I can change plant morphology, depress the growth of plants, inhibit germination or totally or selectively kill plants depending on the amounts used. For application, the compound generally is applied most effectively by formulating it with a suitable inert carrier or surface-active agent, or both. The invention, therefore, also includes compositions suitable for influencing plant growth and combatting unwanted plants, such compositions comprising an inert carrier or surface-active agent, or both, and as active ingredient at least one compound of Formula I.
The term "carrier" as used herein means an inert solid or fluid material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound is mixed or formulated to facilitate its application to the plant, seed, soil or other object to be treated, or its storage, transport and/or handling. Any of the materials customarily employed in formulating pesticides, herbicides, or fungicides, are suitable.
Suitable solid carriers are natural and synthetic clays and silicates, for example, natural silicas such as diatomaceous earths; magnesium silicates, for example, talcs; magnesium aluminum silicates, for example, attapulgites and vermiculites; aluminum silicates, for example, kaolinites, montmorillonites and micas; calcium carbonate; calcium sulfate; synthetic hydrated silicon oxides and synthetic calcium or aluminum silicates; elements such as, for example, carbon and sulfur; natural and synthetic resins such as, for example, coumarone resins, polyvinyl chloride and styrene polymers and copolymers; bitumen; waxes such as, for example, beeswax, paraffin wax, and chlorinated mineral waxes; solid fertilizers, for example, superphosphates; and ground, naturally-occurring, fibrous materials, such as ground corncobs.
Examples of suitable fluid carriers are water, alcohols such as, for example, isopropyl alcohol, glycols; ketones such as, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, and cyclohexanone; ethers such as, for example, cellosolves; aromatic hydrocarbons such as, for example, benzene, toluene and xylene; petroleum fractions such as, for example, kerosene, light mineral oils; chlorinated hydrocarbons such as, for example, carbon tetrachloride, perchloroethylene, trichloroethane, including liquefied, normally vaporous, gaseous compounds, Mixtures of different liquids are often suitable.
The surface-active agent may be an emulsifying agent or a dispersing agent or a wetting agent; it may be nonionic or ionic. Any of the surface-active agents usually applied in formulating herbicides or insecticides may be used. Examples of suitable surface-active agents are the sodium or calcium salts of polyacrylic acids and lignin sulfonic acids; the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols or alkyl phenols, for example, p-octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulfates or sulfonates of these condensation products, alkali or alkaline earth metal salts, preferably sodium salts, or sulfuric or sulfonic acid esters containing at least 10 carbon atoms in the molecule, for example, sodium lauryl sulfate, sodium secondary alkyl sulfates, sodium salts of sulfonated castor oil, and sodium alkyl-aryl sulfonates such as sodium dodecylbenzene sulfonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxides.
The compositions of the invention may be prepared as wettable powders, dusts, granules, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols. Wettable powders are usually compounded to contain 25, 50 or 75% by weight of the active compound and usually contain, in addition to the solid carrier, 3-10% by weight of a dispersing agent, 15% of a surface-active agent and, where necessary, 0-10% by weight of stabilizer(s) and/or other additives such as penetrants or stickers. Dusts are usually formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant or surface-active agent, and are diluted in the field with further solid carrier to give a composition usually containing 0.5-10% by weight of the active compound. Granules are usually prepared to have a size between 10 and 100 BS mesh (1.676-0.152 mm), and may be manufactured by agglomeration or impregnation techniques. Generally, granules will contain 0.5-25% by weight of the active compound, 0-1% by weight of additives such as stabilizers, slow release modifiers and binding agents. Emulsifiable concentrates usually contain, in addition to the solvent and, when necessary, cosolvent, 10-50% weight per volume of the active compound, 2-20% weight per volume emulsifiers and 0-20% weight per volume of appropriate additives such as stabilizers, penetrants and corrosion inhibitors. Suspension concentrates are compounded so as to obtain a stable, non-sedimenting, flowable product and usually contain 10-75% weight of the active compound, 0.5-5% weight of dispersing agents, 1-5% of surface-active agent, 0.1-10% weight of suspending agents, such as defoamers, corrosion inhibitors, stabilizers, penetrants and stickers, and as carrier, water or an organic liquid in which the active compound is substantially insoluble; certain organic solids or inorganic salts may be dissolved in the carrier to assist in preventing sedimentation or as antifreeze agents for water.
Aqueous dispersions and emulsions, for example, compositions obtained by diluting a wettable powder or a concentrate according to the invention with water, also lie within the scope of the present invention. The said emulsions may be of the water-in-oil or of the oil-in-water type, and may have a thick, mayonnaise-like consistency.
The compositions of the invention may also contain other ingredients, for example, other compounds possessing pesticidal, especially insecticidal, acaricidal, herbicidal or fungicidal properties, as are appropriate to the intended purpose.
Influencing plant growth or protection of a locus or area from undesirable plants is effected by applying a compound of Formula I, ordinarily in a composition of one of the aforementioned types, to soil in which the seeds of the (unwanted) plants are present, or to the foliage of the (unwanted) plants. The active compound, of course, is applied in an amount sufficient to exert the desired action.
The amount of the compound of the invention to be used in influencing plant growth or combating undesired plants will naturally depend on the condition of the plants, the degree of activity desired, the formulation used, the mode of application, the climate, the season of the year, and other variables. Recommendations as to precise amounts are, therefore, not possible. In general, however, application to the locus (to be protected) of from 0.1 to 10.0 kg per hectare of the compound of Formula I will be satisfactory.